Utilization of biomass-derived electrodes: a journey toward the high performance of microbial fuel cells

Abstract

This study aims to improve electron transfer and cobalt remediation efficiency through microbial fuel cells (MFCs) by modifying the electrode material. The fabrication and alteration of the anode can be accomplished by synthesizing biomass-derived graphene oxide (GO) and adding metal oxides (ZnO and TiO2) as modifiers. The prepared GO anode offered 0.148 mW/m2 power density while GO-ZnO delivered 8.2 times and GO-TiO2 composite anode delivered 5.3 times higher power density than GO. Similarly, the achieved current density of GO was 39.47 mA/m2 while GO-ZnO composite anode delivered 75.43 mA/m2 and GO-TiO2 composite anode offered 67.54 mA/m2. During the biological characterizations of biofilm, the Bacillus sp. and Klebsiella pneumoniae strains were majorly found as exoelectrogens and metal-reducing species. The maximum remediation efficiency of cobalt (II) was 80.10% (GO), 91% (GO-ZnO composite anode), and 88.45% (GO-TiO2 composite anode) on day 45. The remediation and SEM results of anode biofilm clearly show that the prepared anodes are highly biocompatible with the bacteria. Furthermore, the effect of pH and temperature on MFCs performance are also explained with prepared anodes. Each anode offered significant perspectives in parameter optimizations.